1. Field of the Invention
The present invention relates to a height gauge for measuring a dimension of a workpiece from a height position of a probe elevatable in up and down direction. More specifically, it relates to a height gauge capable of moving on a platen with an easy operation.
2. Description of Related Art
A large height gauge is used for measuring a dimension of a relatively large workpiece, i.e., dimension such as height, level difference, hole and axis.
Generally, a height gauge has a base movably disposed on a platen, a column provided to the base, a slider elevatable along the column and having a probe, and a displacement sensor for detecting a displacement amount in a height direction of the slider.
Since a large height gauge is heavy, an air-floatation mechanism in which base blows air onto the platen for floating the base relative to the platen is sometimes provided for facilitating movement thereof.
Conventionally, such large height gauge having the air-floatation mechanism has a grip 3 provided on a position easy for a floatation switch 4 to be pressed at a backside of the column 2 as shown in FIG. 12.
In operation, the grip 3 is grasped by one hand and the floatation switch 4 is pressed. Then, air is blown out from the base 1 to a platen 10 to float the base 1 relative to the platen 10. In this state, the base 1 is moved while being guided by the other hand. When the probe 5 is located adjacent to a target portion of the workpiece, the floatation switch 4 is released. Then, the air from the base 1 to the platen 10 is shut down so that the base 1 touches the platen 10, and the measurement process is conducted in this state.
In the conventional measurement work, since the worker has to move the base 1 while grasping tie grip 3 opposite to the probe 5 with the column 2 therebetween, it was difficult for the worker to check whether the probe 5 has reached to a position around the target portion of the workpiece, which can result in collision of the probe 5 against the workpiece.
On the other hand, when the worker stands on the probe 5 side for moving the base 1 while checking the status of the probe 5, the worker has to hold the grip 3 by extending the arm to a backside of the column 2, in other words, has to operate in an unnatural posture, and the floatation switch 4 is difficult to be operated. Especially, above work is extremely difficult in a so-called profiling measurement where the height gauge is moved while s touching the probe 5 to the workpiece.
An object of the present invention is to solve the above conventional problem and to provide a height gauge capable of being moved with an easy posture while checking positional relation between the probe and the workpiece and capable of facilitating a switch operation thereof.
The present invention is a height gauge having: a base movable on a platen; a column vertically provided on the base; a slider elevatable along the column and having a probe thereto a displacement sensor for detecting a displacement amount of the slider in a height direction; an air-floatation mechanism for floating the base against the platen by blowing out air from the base to the platen, which is characterized in having a handle on a side of the column adjacent to a probe side thereof around the base or on a base around the side of the column adjacent to the probe side, the handle having an air-floatation control switch for controlling supply and cut-off of air to the air-floatation mechanism.
According to the present invention, since the handle is provided on a side of the column adjacent to a probe side thereof around the base or on a base around the side of the column adjacent to the probe side, the base can be moved from the side adjacent to the probe side by grasping the handle. Accordingly, the handle can be grasped with an easy posture and the movement is possible while confirming whether the probe has reached around a target portion of the workpiece, thereby improving operability.
Especially, since the handle is provided to the column, a height from the platen to the handle can be established at any desired height without requiring special member for securing the height. For example, when the handle is provided to the base, thickness of the base has to be increased or a member for securing the height is required on the base for insuring the height from the platen to the handle. However, since the handle is provided to the column, no special member is required and any desired height can be established from the platen to the handle.
Further, since the air-floatation control switch for controlling supply and cut-off of the air to the air-floatation mechanism is provided to the handle, the air-floatation control switch can be operated while grasping the handle. Accordingly, the base can be moved and stopped on the platen with a single-hand operation.
In the present invention, the handle may preferably have a repeat switch for repeatingly commanding measurement steps of a previous measurement item.
According to the above arrangement, when a plurality of workpiece of the same sort is consecutively measured, the workpiece can be measured while grasping the handle with one hand and exchanging the workpiece with the other hand, thus improving measurement efficiency.
In the present invention, the handle may preferably have a cancel switch for commanding cancellation of the measurement step currently in process.
Accordingly, the measurement step currently in process can be cancelled while grasping the handle with one hand, thus improving measurement efficiency.
In the present invention, the handle may preferably be rotatable around an axis parallel to the column and fixable at any desired rotary angle position.
Accordingly, since the handle can be rotated around an axis parallel to the column, the handle can be turned to an angle easy for operation in accordance with a posture of the workpiece and the worker.
In the present invention, it is preferable that at least an end portion of the handle is inclinable in up and down direction and fixable at any desired inclination angle position.
Accordingly, since at least an end portion of the handle can be inclined in up and down direction, the handle can be operated at a status inclined at any inclined angle position. Further, when the end portion is inclined in up and down direction, the handle does not project in a horizontal direction, thus not impairing accommodatability and portability.
In the present invention, the air-floatation mechanism may preferably be capable of switching status thereof between a status in which the base is completely floated against the platen with a predetermined gap therebetween by blowing air from the base to the platen and a semi-floating status in which the base touches the platen with a weight of the base and a weight applied to the base being reduced by blowing air from the base to the platen.
According to the above arrangement, since the air-floatation mechanism is capable of switching the status thereof between a status in which the base is completely floated against the platen with a predetermined gap therebetween by blowing air from the base to the platen and a semi-floating status in which the base touches the platen with a weight of the base and a weight applied to the base being reduced by blowing air from the base to the platen, the movement can be facilitated while maintaining highly accurate measurement by conducting measurement under the semi-floating status in, for instance, profiling measurement.